The article proposes an improved method for the calculation of the electromagnetic field radiated by a lightning return stroke over a perfectly conducting ground. Specifically, the proposed time domain expressions allow a closed-form solution for the field produced by an impulse-current propagating upward along a vertical path with a given velocity. The expressions are valid for a wide class of engineering return stroke models and can be adopted also in case the return stroke velocity varies along the channel. The solution for an arbitrary current waveform can be obtained by the convolution of the current at the channel base with the electromagnetic field due to the impulse-current along the channel. The accuracy and advantages of the method are assessed by the comparison with those obtained by a finite-element method computer model. The expressions are implemented in the LIOV-EMTP-RV code for the calculation of the induced voltages in an overhead distribution line.

中文翻译：

---

考虑变回程速度的雷电电磁场计算新方法

这篇文章提出了一种改进的方法，用于计算理想导电地面上的雷电回程所辐射的电磁场。具体而言，提出的时域表达式允许以一定速度沿垂直路径向上传播的冲击电流产生的磁场进行闭式解。这些表达式对于多种工程回程模型有效，并且在回程速度沿通道变化的情况下也可以采用。通过沿通道的脉冲电流，通过通道底部的电流与电磁场的卷积，可以获得任意电流波形的解。通过与通过有限元方法计算机模型获得的结果进行比较，评估了该方法的准确性和优势。